Common High Integrity Restrictions (DYN01)

Level \(\rightarrow\) Required

Category

Safety:: \(\checkmark\)
Cyber:: \(\checkmark\)

Goal

Maintainability:: \(\checkmark\)
Reliability:: \(\checkmark\)
Portability:
Performance:
Security:: \(\checkmark\)

Remediation \(\rightarrow\) Low

Verification Method \(\rightarrow\) Compiler restrictions

Reference

Ada Reference Manual: H.4 High Integrity Restrictions

Description

The following restrictions must be in effect:

No_Anonymous_Allocators

No_Coextensions

No_Access_Parameter_Allocators

Immediate_Reclamation

The first three restrictions prevent problematic usage that, for example, may cause un-reclaimed (and unreclaimable) storage. The last restriction ensures any storage allocated by the compiler at run-time for representing objects is reclaimed at once. (That restriction does not apply to objects created by allocators in the application.)

Applicable Vulnerability within ISO TR 24772-2

4.10 Storage Pool

Noncompliant Code Example

For No_Anonymous_Allocators:

X : access String := new String'("Hello");
...
X := new String'("Hello");

For No_Coextensions:

type Object (Msg : access String) is ...
Obj : Object (Msg => new String'("Hello"));

For No_Access_Parameter_Allocators:

procedure P (Formal : access String);
...
P (Formal => new String'("Hello"));

Compliant Code Example

For No_Anonymous_Allocators, use a named access type:

type String_Reference is access all String;
S : constant String_Reference := new String'("Hello");
X : access String := S;
...
X := S;

For No_Coextensions, use a variable of a named access type:

type Object (Msg : access String) is ...
type String_Reference is access all String;
S : String_Reference := new String'("Hello");
Obj : Object (Msg => S);

For No_Access_Parameter_Allocators, use a variable of a named access type:

procedure P (Formal : access String);
type String_Reference is access all String;
S : String_Reference := new String'("Hello");
...
P (Formal => S);

Notes

The compiler will detect violations of the first three restrictions. Note that GNATcheck can detect violations in addition to the compiler.

The fourth restriction is a directive for implementation behavior, not subject to source-based violation detection.